1. Field of the Invention
The present invention is in the field of circulating air systems and pertains more particularly to a stock material adapted to be cut and formed into a fitting for such systems.
2. The Prior Art
It is known in air circulating systems or the like to provide a flexible connector material interposed between rigid duct components, the connector functioning to prevent vibrations present in one duct section from being transmitted to an adjacent section and, hence, throughout the remaining components of the system.
By way of example, flexible connector materials of the type described are illustrated in U.S. Pat. No. 3,214,807 and certain of the patent references therein cited.
Typically, flexible connector material heretofore known has been sold as a stock material in coiled lengths of fifty feet or more and has comprised first and second elongate metal strips, each of which strips has a longitudinal marginal edge connected to a marginal edge of an elongate central fabric web. The resultant construction enables a contractor to sever a length of stock material from the coil and bend the same transversely to match the configurations of the duct.
In use, the formed stock material seals the space between opposed open mouth duct portions by fastening one formed metal strip to the mouth portion of one duct and the other formed metal strip to the open mouth portion of the adjacent duct, whereby the formed stock material provides a continuation of the two duct components, and at the same time reduces transmitted vibration therebetween.
In accordance with modern practice and consonant with the desire to minimize energy loss, it has become standard practice to insulate the metal ducts. While such insulation has taken various forms, the net effect has been to prevent substantial heat loss through the duct material. While insulation of the duct materials themselves has resulted in increased thermal efficiency, substantial losses have been encountered at the interface between ducts spanned by flexible connector material.